Servo Control Of Manipulator Flexible Joint Based On Passivity Theory And Auto Disturbance Rejection

Space manipulators have to complete many complex tasks in space,accompanied by strong external disturbances due to harsh operating environments such as vacuum,weightlessness,and large temperature differences.Therefore,it's meaningful to design a position control strategy with high precision and strong anti-disturbance ability for the space manipulator.As the core component of the space manipulator,joints play a vital role in the smooth operation of the space manipulator.The flexibility of the joint and the output stability of the drive motor all affect the control accuracy of the space manipulator.Therefore,this paper considers the above factors to carry out research on the high-precision position control of the flexible joint manipulator system.Firstly,the interconnection and damping assignment passivity-based control method based on the port-controlled Hamiltonian theory is used to study the speed control of permanent magnet synchronous motors.Research shows that compared to traditional vector control,the passive control method has better dynamic performance and is robust to changes in load torque.However,the dynamic response speed of this method cannot be adjusted arbitrarily according to design requirements.In order to enhance the dynamic response,robustness and anti-disturbance ability of the permanent magnet synchronous motor,a double closed-loop position feedback control system is designed by using the linear active disturbance rejection control combined with interconnection and damping assignment passivity-based control.The simulation results show that the adjustment time of the motor position control system can be adjusted arbitrarily by reasonably configuring the damping and controller bandwidth parameters.And the system has good control performance and anti-disturbance ability.Secondly,the position control of the flexible joint manipulator is studied.Taking the single-link flexible joint manipulator as the research object,based on the establishment of the dynamic model,the double closed-loop position feedback control system is designed by using the linear auto disturbance rejection control method.The outer loop is the position control of the joints,which uses linear active disturbance rejection control;the inner loop is the position control of the motor,which uses linear active disturbance rejection control and interconnection and damping assignment passivity-based control.The simulation shows that by configuring the controller bandwidth parameters of the inner and outer loop,the manipulator has higher trajectory tracking accuracy and robustness.Finally,in order to improve the control performance of the position control system of the flexible joint manipulator under low bandwidth gain,the position control system based on the fractional-order active disturbance rejection control is designed for the flexible joint manipulator.The simulation results show that,compared with the position control based on linear active disturbance rejection control,the fractional-order active disturbance rejection control position control system has faster response speed and higher control accuracy.And it also has good control performance and robustness under low bandwidth gain.